It is known to provide parabolic reflectors for various electric lamps including miners' cap lamps in which the filament of an electric bulb is placed at the focus of a parabolic reflector. Such an arrangement produces a parallel beam of light but as the filament extends beyond the point of the focus of the parabola, there is a slight spread of light around the parallel beam. The disadvantage of this kind of reflector is that at distances of up to 3 meters only a relatively small spot of light is produced and for some applications such as in a miner's cap lamp, this provides a limited area of illumination at the distance of normal operation by the user. The human eye can usually see clearly without moving within an angular spread of about 6.degree. i.e. about 3.degree. on either side of the axis of the eye.
An aim of the present invention is to provide an improved reflector which produces a controlled spread of light which is larger than that of a corresponding parabolic reflector and suited to the requirements of the user.